Various adjustable V belt pulleys have been used so as to vary the pitched diameter at which a V belt runs between two outwardly diverging annular faces and various means have been used to secure such pulleys on a shaft. The prior art adjustable V belt pulleys have been relatively expensive to produce, costly of materials and have required set screws or keys for locking such pulleys on shafts and, accordingly, have posed many problems relative to the economy, installation, maintenance and relative adjustability as such pulleys relate to the range of pitch diameters which such pulleys have accommodated.